Remote System Discovery with Adsisearcher

SPLUNK detection rule by Mauricio Velazco, Splunk · Apache-2.0

The following analytic detects the use of the `[Adsisearcher]` type accelerator in PowerShell scripts to query Active Directory for domain computers. It leverages PowerShell Script Block Logging (EventCode=4104) to identify specific script blocks containing `adsisearcher` and `objectcategory=computer` with methods like `findAll()` or `findOne()`. This activity is significant as it may indicate an attempt by adversaries or Red Teams to perform Active Directory discovery and gain situational awareness. If confirmed malicious, this could lead to further reconnaissance and potential lateral movement within the network.

name: Remote System Discovery with Adsisearcher
id: 70803451-0047-4e12-9d63-77fa7eb8649c
version: 12
creation_date: '2021-09-01'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: TTP
description: The following analytic detects the use of the `[Adsisearcher]` type accelerator in PowerShell scripts to query Active Directory for domain computers. It leverages PowerShell Script Block Logging (EventCode=4104) to identify specific script blocks containing `adsisearcher` and `objectcategory=computer` with methods like `findAll()` or `findOne()`. This activity is significant as it may indicate an attempt by adversaries or Red Teams to perform Active Directory discovery and gain situational awareness. If confirmed malicious, this could lead to further reconnaissance and potential lateral movement within the network.
data_source:
    - Powershell Script Block Logging 4104
search: |-
    `powershell` EventCode=4104 ScriptBlockText = "*adsisearcher*" AND ScriptBlockText = "*objectcategory=computer*" AND ScriptBlockText IN ("*findAll()*","*findOne()*")
      | fillnull
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY dest signature signature_id
           user_id vendor_product EventID
           Guid Opcode Name
           Path ProcessID ScriptBlockId
           ScriptBlockText
      | `security_content_ctime(firstTime)`
      | `remote_system_discovery_with_adsisearcher_filter`
how_to_implement: To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba.
known_false_positives: Administrators or power users may use Adsisearcher for troubleshooting.
references:
    - https://attack.mitre.org/techniques/T1018/
    - https://devblogs.microsoft.com/scripting/use-the-powershell-adsisearcher-type-accelerator-to-search-active-directory/
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: Remote system discovery enumeration with adsisearcher on $dest$ by $user_id$
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Active Directory Discovery
asset_type: Endpoint
mitre_attack_id:
    - T1018
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1087.002/AD_discovery/adsisearcher-powershell.log
          source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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d6f0eb15-9407-470a-8235-ce6d1a305081

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